From 541ab35b4b819152af10f0d9bce31a226422c47b Mon Sep 17 00:00:00 2001
From: Ynse Hoornenborg <github@ynse.nl>
Date: Mon, 15 Jul 2024 18:56:13 +0200
Subject: [PATCH] Fix issue in Transform Unit Count

---
 src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileDecoder.cs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileDecoder.cs b/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileDecoder.cs
index bcb082a721..10fdcdf6cf 100644
--- a/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileDecoder.cs
+++ b/src/ImageSharp/Formats/Heif/Av1/Tiling/Av1TileDecoder.cs
@@ -1357,14 +1357,18 @@ internal class Av1TileDecoder : IAv1TileDecoder
                     }
                 }
 
-                this.transformUnitCount[(int)Av1Plane.U][forceSplitCount] = lumaTransformUnitCount;
-                this.transformUnitCount[(int)Av1Plane.V][forceSplitCount] = lumaTransformUnitCount;
+                this.transformUnitCount[(int)Av1Plane.U][forceSplitCount] = chromaTransformUnitCount;
+                this.transformUnitCount[(int)Av1Plane.V][forceSplitCount] = chromaTransformUnitCount;
             }
         }
 
         // Cr Transform Info Update from Cb.
         if (totalChromaTransformUnitCount != 0)
         {
+            DebugGuard.IsTrue(
+                (transformInfoUvIndex - totalChromaTransformUnitCount) ==
+                partitionInfo.ModeInfo.FirstTransformLocation[(int)Av1PlaneType.Uv],
+                nameof(totalChromaTransformUnitCount));
             int originalIndex = transformInfoUvIndex - totalChromaTransformUnitCount;
             for (int i = 0; i < totalChromaTransformUnitCount; i++)
             {